BENFICA are in the last-chance saloon and will come out with all guns blazing. But, a fired up Celtic are capable of calling the shots.
History is against the Hoops getting anything from their visit to Lisbon, having lost all three previous matches played in Portugal against Benfica.
However, momentum is in their favour, and at least one point can be brought back to Glasgow to keep Neil Lennon's men on track for the Last 16.
It could be an even better outcome of course, and should the Parkhead outlet claim all three points then it is possible that qualification for the knock out rounds could be tied up, if results earlier in the evening in Moscow go their way.
The confidence gained from a hard-fought victory in Russia on match day two has been increased many times over by defeating Barcelona, and this has heralded a dramatic improvement to Celtic's mind set and chances of getting out of this group.
NO says MICHAEL GRANT
CELTIC's win at Aberdeen was instantly forgettable but manager Neil Lennon won't mind if that suggests the pattern of their season isn't going to change any time soon.
Unexciting performances in the SPL and then inspired, memorable ones in the Champions League will do Lennon just fine if that means another rewarding result in Lisbon tomorrow night.
This Champions League group still has the feel of a campaign which will go to the wire, or in other words, the final game at home to Spartak Moscow.
Celtic have transformed into a team that can handle Europe - those collapses in Braga, Utrecht and Sion seem like a lifetime ago - but an entire campaign without defeat is asking a lot.
Benfica are a massive threat and the Parkhead club's record against the club in away from home does not make for promising reading.
It may well all come down to the Russian's trip to Glasgow on December 5.